1. Field of the Invention
The present invention relates to antennas; more particularly, slot antennas.
2. Description of the Prior Art
FIG. 1 illustrates prior art slot antenna 6. Slot antenna 6 includes front panel 10 and rear panel 12 separated by spacers 14. Rear panel 12 is typically made of a conductive material and front panel 10 contains an upper non-conductive layer 16 and a lower conductive layer 18. Microstrip 20 is deposited on the surface of layer 16 to provide a path for the signal to be transmitted or received. The ends of the microstrip extend across slots 22 in conductive layer 18. When a signal to be transmitted is provided on microstrip 20, electromagnetic energy is transmitted in the Z direction with an electric field polarized in the Y direction. Unfortunately, this arrangement provides no control over the beamwidth in the Y-Z plane.
FIG. 2 illustrates a prior art slot antenna having an array of slots; only the microstrip and slots are shown. This slot array antenna is fabricated using a design similar to the design illustrated in FIG. 1. In this configuration, microstrip 30 feeds the signal to be transmitted across slots 32. This results in electromagnetic energy being transmitted in the Z direction with an electric field polarization in the Y direction. In FIG. 2, the Z direction is the direction coming out of the figure toward the viewer. Once again, this design does not provide beamwidth control in the Y-Z plane.